The present invention relates to optical fiber connectors and, more particularly, to a duplex clip that is clipped to the buffer adapters, or boots, disposed on the ends of two optical fibers to form a duplex connector.
In networks and communication equipment that utilize optical fibers, it is frequently desirable to make a connection with a pair of optical fibers and to ensure that the connections have been made correctly. For example, it is important to ensure that a transmitting optical fiber is connected to the transmitter port of a transceiver and that the receive optical fiber is connected to the receiver port of the transceiver. Similarly, it is important that when a pair of transmit and receive optical fibers are to be connected to another pair of transmit and receive optical fibers, the correct optical fibers of each of the pairs are connected together, or optically coupled at their ends. Otherwise, an end of a transmit optical fiber of one pair may be connected to an end of a receive optical fiber of the other pair, which, for obvious reasons, is unacceptable. Properly orienting the optical fibers in this manner ensures that the optical fibers are connected with the proper polarity.
Duplex optical connectors have been utilized in the communications industry to couple two simplex optical fibers together in a duplex arrangement to allow both optical fibers to be simultaneously connected to ports located on communication equipment or to an adapter that connects pairs of optical fibers together. For example, U.S. Pat. No. 4,787,706 discloses a duplex optical fiber connector for terminating a cable containing a pair of buffered optical fibers. Each of the optical fibers is held within a fiber-holding assembly comprising a ferrule and a spring-loaded base member. The fiber-holding assemblies are contained within a common housing that is formed to include two flexible molded plastic side arm members for interlocking with a mating receptacle. The housing includes details that can be used to ensure that when the optical fiber connector is connected with another optical fiber connector, the connection is made with the proper polarity.
U.S. Pat. No. 5,579,425 (hereinafter the ""425 patent) also discloses an optical fiber duplex connector, which is shown in FIG. 1. The duplex connector is constructed by joining together a pair of simplex connectors 1 with a plastic clip 2. Each clip 2 includes a first planar structure 3 having a pair of cylindrical pins 4 of different diameters thereon, which are press fit into associated openings 5 formed in the simplex connectors 1 to thereby connect them together. The plastic clip 2 has information thereon, such as the letters A and B, that may be utilized by a user to identify the correct polarization of the duplex connector with respect to an adapter (not shown) into which it is plugged.
Although the plastic clip disclosed in. the ""425 patent is suitable for use with the type of simplex connectors shown in FIG. 1, which are normally connected to the front side of a connector receptacle or adapter, this clip 2 is not suitable for use with behind-the-wall (BTW) connectors. BTW connectors are connected on the back side, commonly referred to as the junior side, of the receptacle or adapter where there is typically very little room. The confined area dictates that the simplex connectors and the boots associated therewith generally be shorter in length than the boots 7 of the cables 6 that are used with the simplex connectors 1 in front side mounting configurations.
On the front side of the connector receptacle or adapter, there generally is plenty of space and the length of the connector 1 and the boot 7, which is also referred to as a cable support, is not an issue. Therefore, the plastic clip 2 disclosed in ""425 patent, which connects to the housings of the connectors 1, is suitable for use in this type of environment since the lengths of the housings normally are sufficiently long to accommodate connection with the clip 2 at locations near the back ends of the housings. However, this generally is not true with respect to connectors used in BTW configurations.
FIG. 2 illustrates another known optical fiber duplex connector. The duplex connector shown in FIG. 2 comprises two connectors 10 that are clipped together by a duplex yoke 11, which attaches near the back ends of the connector housings. Once the duplex yoke 11 has been attached, end portions of two strain relief boots 12 are pushed over crimp cans 13 extending from the back ends of the connector housings. Heat fit tubing 14 is attached to the fiber cable 15 and to the ends of the crimp cans 13. Each of the connectors 10 is comprised of a two-piece housing. The front portion 16 of the housing has a latch 17 thereon and houses the ferrule assembly (not shown) that holds the end of the optical fiber. The back portion 18 of the housing contains a metal insert (not shown) that assists the connector in handling side loading. The optical fiber cable 15 contains aramid fiber strength members that are crimped to the metal insert.
As with the duplex connector of the ""425 patent, the duplex yoke 11 attaches to the connector housings. The housings of the connectors 10 are sufficiently long to enable the yoke 11 to be attached to them because the connectors 10 require the back portions 18 of the housings, which contain the metal inserts that provide the connectors 10 with sufficient side loading capability. As with the duplex connector of the ""425 patent, the duplex connector shown in FIG. 2 normally is used on the front side of receptacles or adapters rather than on the junior side. Connectors utilized on the front side normally must have greater strain relief and side loading capability, since they are normally disposed in environments where they are susceptible to greater bending forces and typically use larger cordage. Therefore, these jumper connectors typically are longer than BTW connectors and are therefore capable of being clipped together by a duplex yoke that attaches to the connector housings. However, the duplex yoke shown in FIG. 2 is not suitable for use with BTW connectors typically used on the junior side of an adapter or device receptacle in BTW mounting arrangements for the same reasons that the duplex clip of the ""425 patent is not suitable for use in such arrangements.
FIG. 3 is a side view of an optical connector that is typically used in a BTW configuration and which is suitable for use with the duplex clip of the present invention. The connector 20 shown in FIG. 3 comprises a plug body 21 and a rear extender cap 22. The plug body 21 has keyways 23xe2x80x9423 formed in opposite sides thereof. The rear extender cap 22 has keys 24xe2x80x9424 disposed on opposite sides thereof. The plug body 21 is coupled to the extender cap 22 by snapping the keys 24xe2x80x9424 located on each side of the plug body 21 inside of the keyways 23xe2x80x9423 formed on each side of the extender cap 22. The extender cap 22 is coupled to a buffer adapter 25, or boot, which protects a buffered optical fiber (not shown). The boot 25 is comprised of a wide cylindrical portion 26, which fits over an end of the extender cap 22, a tapered cylindrical portion 27, which resists side pulling and ensures a proper minimum bend radius, and a narrow cylindrical portion 28, which protects the buffered fiber from kinking that might otherwise result from light sidepulling forces. The plug body 21 has a latch 29 molded thereon that enables the connector 20 to be coupled to and decoupled from a receptacle or adapter.
The connector 20 shown in FIG. 3 is typically considerably shorter in length than the two-piece connectors 1 and 10 shown in FIGS. 1 and 2, respectively, which makes the connector 20 suitable for use in BTW configurations. It would be desirable to provide a duplex clip capable of coupling two simplex connectors of the type shown in FIG. 3 together to form a duplex connector. However, due to the relatively short length of the housing of the connector 20, a duplex clip is needed that is capable of coupling two shorter simplex connectors together to form a duplex connector.
In BTW mounting configurations, the connectors that terminate the ends of the receive and transmit optical fibers must be connected to the receive and transmit ports located in the junior side of a receptacle or adapter. Therefore, the receive and transmit optical fibers must be correctly polarized on the junior side of the housing in the same manner in which the receive and transmit optical fibers must be correctly polarized on the front side of the receptacle or adapter. However, currently there is no aid for assisting a user or technician in determining the polarity of the optical fibers connected on the junior side. Therefore, once the transmit and receive optical fibers have been connected to the ports on the junior side, if a user removes one or both of the optical fibers from their respective ports, the user must somehow keep track of which simplex connector is to be connected to which port in order to ensure that the connectors are properly polarized when they are re-connected to the transmit and receive ports.
It would be desirable to provide a duplex clip that converts two simplex connectors into a duplex connector for use in cases where there is very little room to work with the connectors and/or in cases where the housings of the connectors are too short to enable the housings to be coupled together to form a duplex connector. For example, with respect to the connector 20 shown in FIG. 3, once the connector 20 has been inserted into an associated adapter or receptacle, most of the body of the connector 20 is contained within the adapter or receptacle. The portion of the connector body that is not contained in the adapter or receptacle generally is insufficient to enable a duplex clip to be attached thereto for the purpose of clipping two of the connectors together to form a duplex connector.
Accordingly, a need exists for a duplex clip that is capable of clipping two simplex connectors together to form a duplex connector, which is suitable for use with connectors used in BTW configurations and in other confined areas, and which helps a user to easily determine the polarity of the connectors.
The present invention provides a duplex clip for clipping a pair of simplex connectors together to form a duplex connector. Simplex connectors typically comprise a generally rectangular housing having a plug end for insertion into a mating receptacle or adapter, a cable entrance end for receiving a cable containing a transmission medium, and a boot attached at one end of the boot about the cable entrance end of the housing and at the other end of the boot about the cable. The cable passes through the opening formed in the boot and into the cable entrance end of the housing. The duplex clip comprises a clip body that is adapted to receive and grip the outer surfaces of the boots of the pair of simplex connectors to hold the simplex connectors in close spatial proximity to one another to thereby form a duplex connector.
In accordance with the preferred embodiment of the present invention, two generally cylindrical bores are formed in the clip body and the inner surfaces of each of the bores are adapted to grip the outer surfaces of the boots. Slots are formed in the clip body to provide the bores with generally C-shaped cross-sections. Cables can be passed through the slots to enable the clip to be clipped onto a pair of simplex connectors when the simplex connectors are either coupled to or decoupled from a receptacle or adapter. The clip has markings thereon that enable the polarity of the cables held in the clip to be easily ascertained.
These and other objects and features of the present invention will become apparent from the following description, drawings and claims.